In order to get a feel for the diversity of vegetation and landscapes in South Africa, I planned a 3 week road trip to explore some of the natural areas and botanical gardens across the country. The Western Cape is recognized as having the highest concentration of endemic plant species and containing the main components of the Cape Floristic bioregion. Although this region is usually the one most often visited and considered to be of high floristic interest by the international community, the rest of South Africa is also extremely rich in its floral diversity. With large variation in geology, altitude, seasonal and quantity of rainfall, all of these factors have influenced the various distinct biomes that make up South Africa. During the trip I visited all of the major biomes focusing on seeing natural areas that represent the unique flora of that particular region. Biomes included Fynbos, forest, thicket, grassland, savanna, succulent and Nama Karoo. This post will go through various locations visited throughout the trip.
On the first portion of my journey I headed down to the area known as the Garden Route. The area has received such a name not for the abundance of cultivated landscapes but for the stretches of coastal forest that dominate the landscape. This area has a distinctively different feel compared to the shrub-dominated West Coast or the sub tropical East Coast. A popular destination because of the area’s iconic cliffs steeply descending into the ocean and the unique forests, it’s the smallest of any of the biomes in South Africa.
Baviaanskloof is a 1.2 million acre nature reserve located in the Eastern Cape province. It is a UNESCO World Heritage site featuring both endemic flora and important archeological sites of early human inhabitants. It is thought that people have inhabited the area for as far back in time as the Middle Stone Age (ca. 100,000 – 30,000 B.C,). The flora of this region can differ significantly depending on the altitude and exposure of the landscape. Deep river valleys that often bisect the mountains in the region can support small patches of forest vegetation. The thicket biome is predominantly covered with shrubs and small trees, many with succulent adaptation. Considered almost to be a transitional zone, one will find components of many of the other biomes closely associated such as species allied with members of the succulent Karoo in open valleys and hilltops, to forests in riverine gullies to Fynbos elements in the higher mountainous regions.
GREAT TREK – East Side
Umtamvuna Gorge in the province of KwaZulu-Natal features deep sandstone cliff faces that support coastal forest in the low lands and grasslands on the upper elevations and rims of the canyon. This and the few other gorges in the region support a high diversity of tree species and endemism; for example, the Oribi Gorge which is less than 60 km (37 miles) with similar geology but only share 24% of the same 1514 angiosperm species. (A synfloristic comparison of Oribi Gorge and Umtamvuna Nature Reserves, T.J. Edwards 1998) These gorge systems have preserved flora of older plant species lineage, acting as a site of refuge while also being subject to invasion of the newer lineages of species as climate changed, introducing new flora to the region.
Durban Botanical Gardens
Durban Botanical Gardens sits in the middle of the bustling, busy, third largest city in South Africa. Located on the Eastern Coast it receives summer rainfall and is considered to be semi tropical in the plant communities it supports. Durban Botanical Garden is unique for a number of reasons. It is South Africa’s oldest surviving botanical garden with its establishment in 1851. It is managed by the city itself and the administration is carried out in coordination with a number of municipal partners. This is a notable difference from the majority of gardens I have visited up this point with most of them either being private collections or under the purview of the South African National Biodiversity Institute (SANBI). SANBI gardens such as the internationally known Kirstenbosch are interesting in their own right typically displaying strictly local and native flora and usually containing large natural areas adjacent to the gardens themselves, but do not showcase or grow non-native plants. Durban Botanical Garden, on the other hand ,grows and has a focus on exotic plants not necessarily native to South Africa or the African continent. Historically its development had more of a European and British influence with a focus on introduction of plants of economic value into the country and to catalog flora of South Africa for international partners such as the Royal Botanical Gardens Kew. This English- influenced history can be felt in the garden’s design and historical elements such as the footprint of an old Victorian glass house. In the past, Durban was noted as playing a major role in the introduction of valuable horticultural crops into the country including sugar cane, coffee and pineapples, many of which are still grown in the farmland around Durban. The garden effectively acted as a pipeline to help build agrarian practices and support food security in South Africa. Under the guidance of farmer, botanist and Curator John Medley Wood, the garden undertook the construction of an herbarium to further progress the collecting, identification and exploration of the native flora of the Kwazulu-Natal region. To date the herbarium is still functioning with over 100,000 specimens, although it is now under the administration by SANBI.
The garden was originally established in 1851 and with a suitable climate to support trees the garden has a well developed arboretum with interesting specimens from across the world. This, along with the garden’s formal design, gives this landscape a highly unique feel for a South African garden. In the last few decades the garden was highly diverse in terms of the types of horticulture the institute supported: from extensive ornamental Canna displays and hybridizing dating back to the 1960’s; to growing and displaying a full taxonomic and collection of the genus Erythrina; to anthropologically significant plants such as Ficus religiosa (the fabled tree under which the Buddha reached enlightenment while meditating); to plant conservation such as growing Encephalartos woodii, a robust tree cycad that is extinct in the wild and only grows in cultivation. Having such a diversity of plantings and program support is in many ways the ideal for botanical gardens reaching across disciplines and providing an engaging environment that can bring the art and science of horticulture to the public.
Kruger National Park
Kruger National Park is in South Africa’s Savannah biome and characterized by the grassland vegetation with sparse trees cover. Major drivers of the ecology of this biome are minimal rainfall, fire and grazing by hordes of large animals. This biome is the largest in South Africa comprising almost 50% of the land area and is what is famed to support the iconic large populations of classic African fauna including lions, elephants, panthers, rhinos, giraffes and hippos. This biome extends north into the adjacent countries in Africa including Botsawana, Namibia and Zimbabwe. Development of land in this biome as been kept to a minimum likely from the unsuitability for farming, the lack of reliable water and the presence of malaria in the area.
Walter Sizulu National Botanical Garden
Walter Sizulu National Botanical Garden is situated in the sprawling urban center of Johannesburg. With its metropolitan location, it is the second most visited garden in the country next to Kirstenbosch. I had the privilege of touring the collection with Assistant Curator Andrew Hankey, both a kind and fascinating individual with extensive plant and natural history knowledge of South Africa. Andrew has been with the Garden since the late 1980’s, less than a decade after the Garden was established. With much of the Garden’s improvements occurring within the last 30 years of his tenure, it was a privilege to have the landscape interpreted through one of its principle developers.
Walter Sizulu is tucked in away in a small river valley flanked by cliff sides and sloping hills that are managed as nature reserves adjacent to the Garden. After driving through suburban sprawl and neighborhoods protected by a maze of high, barbed wire and electric fencing, arrival in the tranquil environment of the Garden is a stark contrast to the area’s surroundings. The Garden is located in a steep valley with cascading waterfalls, wandering rivers and steep cliff faces. Acting in a similar manner as the trails that meander Ithaca’s gorges, such as Cascadilla or Six Mile Creek, the contrasting topography of steep slopes and gorges effectively acts as a façade, transporting the visitor out of the built environment and into a wild world. It is no surprise that this garden has become an urban oasis.
The Garden is designed around the river whose path playfully wanders throughout the extent of the Garden. The source of the river is a cascading waterfall on the eastern extent of the property, which acts a reference point and is an iconic feature of the Garden. In an effort to intersperse the natural environment with the cultivated, the Garden’s development attempted to find a balance between the two extremes. As a general rule, if pathways and gardens were designed in close proximity to one side of the river, the area directly on the opposite side of the river was not developed. The intent has been to keep corridors available for the plant and animal life to be able to connect to this important water source, move freely, and have access to the Garden’s larger natural areas on its fringes. This naturalistic design provides both an ecosystem service to the biota of the region and also gives the Garden a playful feel, keeping the visitors engaged by tempting them to explore and find out what secrets are hidden beyond the next bend in the river.
The Garden focuses on both researching and growing the native flora and has also done a magnificent job at designing a number of interesting gardens to draw in the public’s attention. More formalized features include an arboretum, water wise garden, succulent garden, muti (medicinal) garden, fitness garden, geological garden, grasslands garden, children’s garden and cycad garden.
As with other national botanical gardens, some of the most interesting plants that are of research or conservation value are kept in the nurseries behind the scenes in the formal “collection”. Walter Sizulu Gardens was no exception. Vast holdings of succulents focusing on genera of the summer rainfall region were tightly packed into one of the larger greenhouse facilities. Far less precisely order as the contrast Karoo Botanical Gardens, Walter Sizulu had no shortage of fascinating succulent genera and diversity representing the mind boggling diversity of the country.
One of the primary plant conservation efforts the Walter Sizulu is working on is the preservation of Dioscorea strydomiana a member of the yam family (Dioscoreaceae). This species was only recently discovered (2003) and described (2010). Wild populations are under threat because they are subject grazing from large animals as well as collection for traditional African medicine. Less than 200 individuals of this species are known to exists in the wild. It is recognized by Royal Botanical Gardens Kew as one of the most endangered plants in the world. In an effort to preserve the species, Andrew and the Garden have been busy working on developing horticultural practices to grow the plant in ex-situ collections. The effort is to both see if the plant can be grown horticulturally to provide a medicine source without wild collecting as well as to establish new populations in a cooperating nature reserve. One of the hardest challenges with cultivation of medicinal plants for the Muti markets (traditional plant medicine markets) is the perception by the public that plants grown in cultivation don’t possess the same medicinal properties as wild collected ones. This is a similar belief to the traditional medicine practices in China where people believe that the more scarce the plant the more powerful it is. To some extent this has actually been proven true by the fact that plants grown in cultivation oftentimes are growing in ideal conditions. Often many of the medicinal compounds found in these plants develop as secondary metabolites that are generated in greater concentration in response to stressful conditions. This poses a particular challenge, but not an insurmountable one, as it pushes the horticulturalist to grow plants under “controlled” stressed environments.
And now, last but not least, just a few more pictures of interesting specimens from the collection.